JP6477694B2 - Molecular sieve adsorbent formulation and use thereof - Google Patents

Description

  The present invention relates to a molecular sieve adsorbent formulation and its use (use).

A combination of a zeolite and a silicon-based binder, and preferably a seed, which in one embodiment contains a clay binder, preferably formed by a granulation process that has been utilized in the manufacture of molecular sieve formulations. molecular sieve formulation containing, as well as preparation and use of these molecular sieve formulation (e.g., liquid, dehydration of gases or vaporous hydrocarbon stream, drying of the cracked C ₁ -C ₄ cracked hydrocarbon gas stream, There are various aspects of dehydrating the ethanol feed stream and removing various undesirable materials from the various feed streams.

  Here, for the purposes of this disclosure, the term “molecular sieve formulation” is interchangeable with “adsorbent”, “adsorbent formulation”, “molecular sieve adsorbent formulation” or “molecular sieve adsorbent”, etc. Called.

Zeolite is a hydrated metal aluminosilicate represented by the following general formula:
M _{2 / n} O: Al ₂ O ₃ : xSiO ₂ : yH ₂ O
Here, M usually means an alkali or alkaline earth metal, n is the valence of the metal M, x is a number ranging from 2 to infinity, depending on the structure type of the zeolite, y Indicates the hydration state of the zeolite. Most zeolites are three-dimensional crystals with a crystal grain size in the range of 0.1-30 μm. Heating such zeolites to high temperatures results in the loss of hydrated water, resulting in a crystalline structure with molecular sized channels, providing a high surface area for the adsorption of inorganic or organic molecules. The adsorption of these molecules depends on the pore size of the zeolite channel (pore). The adsorption rate is limited by the diffusion law.

  Zeolites are used in many processes. The choice of zeolite is important in many chemical processes well known to those skilled in the art. For example, interesting catalytic processes using zeolites in the petrochemical industry include reforming, hydrocracking (hydrocracking), dewaxing, isomerization, fluid catalytic cracking (FCC), partial oxidation, alkylation and aromatics. Disproportionation can be mentioned. Zeolites are also used for dehydration, adsorption of various compounds from the feed stream, and separation of various hydrocarbons in the feed stream.

Molecular sieves have been advantageous for many processes because they can promote the diffusion of materials entering and exiting the pores based on the pore size present in the molecular sieve. (For purposes of this disclosure, “zeolite” and “molecular sieve” have the same meaning.)
One limitation in the use of zeolite is that its particle size is very small. Large agglomerates of naturally formed zeolite crystals are easily broken apart. In addition, a fixed bed containing only such fine zeolite crystals has a very high pressure drop when passing through it, so such zeolite crystals are produced by natural gas drying, air drying, and gas flow. It cannot be used alone in a fixed bed for various dynamic applications such as separation of impurities, separation of certain gas or liquid product streams, and the like. Therefore, it is necessary to make such fine zeolite crystals agglomerated with a binder material to obtain a zeolite crystal-containing agglomerate with reduced pressure drop.

  In order to overcome such problems and enable the use of zeolite crystals, various types of clays have been used as binder materials for zeolite crystals. Clay binders have generally been selected from attapulgite, palygorskite, kaolin, sepiolite, bentonite, montmorillonite, other types of clay, and mixtures thereof. Particularly useful clay binders are those formed from attapulgite.

  In one example of the use of a molecular sieve adsorbent, water is removed from a cracked gas stream, for example for ethylene production. In this case, since the molecular sieve adsorbent is used immediately before the low-temperature process for removing water, ice is not generated during the process. However, inherent to this process is that the hydrocarbon feed stream contains highly reactive unsaturated hydrocarbons such as alkenes and dienes. These unsaturated hydrocarbons tend to form oligomers and polymers, and these oligomers and polymers become bed (adsorbent bed) deposits commonly called green oil or coke. These deposits block the adsorption channel, reduce the working capacity of the dehydration bed, and reduce the effective adsorption life of the adsorbent. Therefore, it is also important that the molecular sieve adsorbent produce very little green oil or coke during the adsorption process.

  Many of the clay binders traditionally used as binder materials with zeolites contain metal acid sites that facilitate polymer / oligomer formation by catalysis. Conventionally, such clay binder materials have been treated with an inactivating agent such as a phosphoric acid solution to reduce this catalytic activity. Nevertheless, the problems associated with the formation of green oil / coke during the hydrocarbon feed stream treatment process when using clay material as a binder material for zeolites still remain.

  Silicon-based materials have sometimes been used as binder materials for high silica molecular sieves to form catalyst masses for special catalytic (catalytic) reactions. Examples of the molecular sieve used in this case include ZSM-5, Y zeolite, and SAPO zeolite. Since both silicon-based binders and high silica zeolites are hydrophobic, such catalytic materials have been limited in their use in organic reactions. For example, a hydrophobic high-silica zeolite blended with a hydrophobic silicon-based binder includes reactions involving reforming, hydrocracking, dewaxing, isomerization, partial oxidation, alkylation, and disproportionation of aromatics Therefore, it has been used as a catalyst material in the petrochemical industry, particularly as a fluid catalytic cracking catalyst.

These catalytic reactions typically utilize hydrophobic zeolites with a high silica content, such as a SiO ₂ : Al ₂ O ₃ ratio of at least 50, preferably more than 200 and as high as about 600. These zeolites are often subjected to dealuminization to increase the silica: alumina ratio in order to enhance their high silica content, thereby making them more hydrophobic. The silicon-based binder used for these catalysts is also required to be highly hydrophobic. Binders used to produce catalysts for these catalytic reactions are not included in this disclosure. Furthermore, the binders of the present disclosure have not previously been utilized to form these catalysts.

  One problem with many conventionally formed zeolite bulk blends is low diffusion. The larger the particle size of the formed zeolite, the lower the diffusion rate of the adsorbed molecules. In particular in the field of pressure swing adsorption, this effect has a very negative effect on short cycle times and thus on productivity. Improvement of the dynamic speed value, that is, speeding up of mass transfer results in shorter cycle time and lower power consumption, thus increasing adsorbent productivity.

  Another important point in selecting an appropriate adsorbent is that adsorption can selectively adsorb only the compounds that are desired to be removed from the feed stream to be processed without adsorbing one or more desired components of the feed stream. The ability of the agent. For example, an important feature of an adsorbent used to remove water from an ethanol feed stream is not only its water adsorption capacity, but also the small amount of ethanol it adsorbs. Often it is necessary to balance the relative adsorption capacity of this type of adsorbent.

  Accordingly, one object is to disclose a method for producing a molecular sieve formulation that is effective and highly selective for removing (dehydrating) water from hydrocarbon feed streams such as those containing ethanol or cracked gas. is there.

Yet another object is to disclose a molecular sieve formulation that can maintain its physical properties and diffusion capacity with less binder amounts commonly used.
Yet another object is to disclose a molecular sieve formulation that produces less undesirable oligomers and polymers when utilized.

Another object is to disclose a method of making a molecular sieve formulation with increased diffusion rate.
Yet another object is to disclose a method of making a molecular sieve formulation containing a silicon-based binder that is effective and selective in the adsorption process, preferably hydrophobic.

  Yet another object is to disclose a molecular sieve formulation comprising a low silica zeolite, preferably hydrophilic, and a silicon-based binder, preferably hydrophobic.

  Yet another object is a molecular sieve formulation comprising a low silica zeolite, preferably hydrophilic, a silicon-based binder, preferably hydrophobic, and a seed (in one embodiment including a clay binder), Disclosed is a molecular sieve formulation that utilizes a granulation seed process in the production of seeds used to make the molecular sieve formulation.

  Yet another object is to combine a low silica zeolite, preferably hydrophilic, with a silicon-based binder, preferably hydrophobic, and a seed, preferably containing a clay binder, Disclosed is a molecular sieve formulation in which the granulated seed method is utilized in production and the seed utilized in the granulated seed method comprises less than 25% by volume of the molecular sieve formulation.

  Yet another object is to mix a low silica hydrophilic zeolite with a hydrophobic silicon binder and a seed, preferably one containing a clay binder, and a granulated seed method is used to produce the seed, and Disclosing a molecular sieve formulation wherein the seed composition comprises clay and a hydrophilic zeolite, the clay comprising less than 5% by weight of the total molecular sieve formulation.

  Yet another object is a molecular sieve formulation comprising a low silica hydrophilic zeolite, a hydrophobic silicon-based binder and a seed used in the preparation of the molecular sieve formulation, preferably a seed containing a clay binder and a hydrophilic zeolite. Disclosed is a method for drying a feed stream comprising passing the feed stream over.

  Yet another object is to provide zeolites, especially low silica hydrophilic zeolites, more specifically low silica hydrophilic zeolites 3A, hydrophobic silicon binders, especially hydrophobic colloidal silica binders or hydrophobic siloxane systems in less preferred embodiments. Disclosed is a method for separating polar materials using a molecular sieve formulation comprising a binder and a seed used in the preparation of the molecular sieve formulation, preferably a seed comprising a clay binder and a hydrophilic zeolite.

  Yet another object is a method for separating components of a gas or liquid feed stream, in particular an ethanol feed stream, comprising a low silica hydrophilic 3A zeolite powder, a hydrophobic colloidal silica binder or, in a less preferred embodiment, a hydrophobic siloxane based binder. And a seed used in the preparation of the molecular sieve formulation, preferably comprising a clay binder and a hydrophilic zeolite, the method comprising passing said gas or liquid feed stream over a molecular sieve formulation That is.

  These and other objects are derived from the methods of manufacture, methods of use and products of the various aspects disclosed herein.

  One embodiment is a molecular sieve formulation comprising a zeolite, particularly a low silica hydrophilic zeolite 3A, and a silicon-based binder, particularly a hydrophobic colloidal silica binder or, more preferably, a hydrophobic siloxane binder. It is a manufacturing method.

  In another embodiment, a zeolite, particularly a low silica hydrophilic zeolite 3A, is blended with a silicon-based binder, preferably a hydrophobic one, and a seed, wherein a granulated seed method is used for the production of the seed. The seed preferably contains a clay binder and the zeolite, and the clay binder comprises less than 5% by weight of the molecular sieve formulation, as well as a process for making the formulation.

  Another aspect is a method of drying a gas or liquid hydrocarbon feed stream, such as an ethanol feed stream, to a zeolite, particularly a low silica hydrophilic zeolite 3A, to a silicon-based binder, particularly a hydrophobic colloidal silica binder or more preferably In a non-embodiment, there is a drying method comprising passing the feed stream over or in a molecular sieve formulation containing a hydrophobic siloxane-based binder.

  Another aspect is a method for separating multiple components of a gaseous or liquid hydrocarbon feed stream, in a zeolite, especially a low silica hydrophilic zeolite, in a silicon-based binder, especially a hydrophobic colloidal silica binder or in a less preferred aspect. A separation method comprising passing the feed stream over or in a molecular sieve formulation comprising a hydrophobic siloxane-based binder.

  Another aspect is a method of drying a gas or liquid hydrocarbon feed stream, such as an ethanol feed stream, or a method of separating multiple components of a gas or liquid hydrocarbon feed stream, to a zeolite, particularly a low silica hydrophilic zeolite. A silicon-based binder, in particular a hydrophobic colloidal silica binder or, in a less preferred embodiment, a hydrophobic siloxane-based binder, and a seed, preferably comprising a clay binder and the zeolite, wherein the seed A granulated seed process is used to produce a dry or separated consisting of passing said selected feed stream over or in a molecular sieve formulation comprising less than 5% by weight of the molecular sieve formulation Is the method.

US Pat. No. 6,458,187

2 shows the maximum temperature rise during the testing process for the various sample products described in Example 1. FIG. 3 compares the reactivity of various sample products from Example 2 for 1,3-butadiene production. FIG. 6 is a diagram comparing dynamic rate data of water adsorption of various sample products from Example 3. It is the figure which compared the water adsorption speed of the various samples from Example 4. FIG. It is the figure which compared the water adsorption capacity of the various products from Example 4. It is the figure which compared the performance of the various adsorbents from Example 1 based on the relationship between the pore distribution coefficient (PDC) and the unused bed length (LUB). It is the figure which compared the methanol and water co-adsorption rate (%) of the zeolite 3A of the comparative example 7 calcined at various calcining temperatures when the potassium ion exchange rate of the zeolite 3A was 50%.

  In addition to the benefits and improvements disclosed above, other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings. The accompanying drawings constitute a part of the specification and include exemplary embodiments and illustrate various objects and features thereof.

  One aspect of the present invention is a molecular sieve formulation comprising a zeolite, preferably hydrophilic, and a silicon-based binder, preferably hydrophobic, and methods for forming and using such formulations. And a method for producing these blends.

  These aspects are unexpected because the adsorption rate and selectivity of the molecular sieve product depend not only on the choice of zeolite but also on the type and nature of the binder incorporated into the zeolite to form the molecular sieve formulation. Based on discovery. It has been unexpectedly discovered that when the same type of zeolite is blended with different types of binders, depending on the binder used, a zeolite formulation is displayed that exhibits quite different performance characteristics. (For purposes of this disclosure, “adsorption rate” or “absorption rate” or “sorption rate” or “mass transfer rate” refers to the amount of adsorbate loading in a feed stream within a certain time in a particular adsorption process. Meaning rate of change).

  The prior art suggests that the adsorption rate and selectivity of a molecular sieve adsorbent depends on the porosity and particle size of the molecular sieve alone. The prior art also suggests that the adsorption rate and selectivity of the molecular sieve used in the hydrocarbon feed depends also on the hydrophobicity of each component of the molecular sieve formulation. For example, conventional zeolite adsorbent formulations that have been used in hydrocarbon feed streams both utilize zeolites and binders that are hydrophobic. That is, when a zeolite blend is used in a conventional process for nonpolar separations such as removal of volatile organic compounds (VOCs), the zeolite: binder system usually consists of two components, both of which are generally hydrophobic. is there. In contrast, zeolite formulations that have been used so far for polar separations such as dehydration from methanol or cracked gas are usually composed of a hydrophilic zeolite: binder system of either component.

  It has now been unexpectedly discovered that the type of binder used to bind the zeolite crystals plays an important role in the adsorption rate and selectivity of the zeolite blend. In addition, when it is desired to perform polar separation such as water adsorption from a hydrocarbon feed stream, the use of a combination of a hydrophilic zeolite and a hydrophobic silicon-based binder is unexpectedly effective for water removal, and a conventional zeolite It has been unexpectedly discovered that it exhibits unexpectedly improved performance compared to the formulation. This improvement includes, but is not limited to, a reduction in green oil or coke production, an improvement in adsorption characteristics, and an improvement in selectivity.

  The zeolite used to produce the molecular sieve formulation according to the present invention may be in any form. Preferably, the zeolite is in the form of crystals, crystal aggregates, or mixtures thereof. It is also possible to use a mixture of different types of zeolites in the production of the molecular sieve formulation according to the invention. In the context of the present invention, “molecular sieve blend” means a blend of multiple materials that can be formed into a shaped material suitable for the desired adsorption process. The molecular sieve formulation is formed by preparing a mixture comprising one or more zeolites, one or more binders, and in a preferred embodiment further seeds formed by granulation. It is preferable. This mixture is then further processed as described herein, for example, formed into a desired shape and calcined.

  In one preferred embodiment, the molecular is obtained by using a mixture comprising or consisting of one or more preferably hydrophilic zeolites and one or more preferably hydrophobic silicon-based binders. A sieve formulation is produced. Various zeolites can be used to form this type of adsorbent formulation, depending on the material to be adsorbed and the material remaining in the feed stream. Additional compositions of binder materials that utilize a seed granulation process are described below.

  Various types of zeolites that have been used for adsorption of various materials include, for example, zeolite A, zeolite X, zeolite Y, zeolite ZSM-5, zeolite β, synthetic mordenite (mordenite), and blends thereof. . For the ion exchange of these zeolites, alkali and / or alkaline earth metals are generally used, although this may not be the case. The crystal grain size of the zeolite as used to produce the molecular sieve formulation of the present invention is preferably in the range of 0.1 to 30 μm.

  One example of an adsorbent system using the molecular sieve formulation disclosed herein adsorbs water from an ethanol stream. For ethanol dehydration, ethanol is the main process inhibitor, since ethanol is the main component in the process feed mixture. The co-adsorption of ethanol is: 1) the water adsorption sites of the zeolite become occupied or clogged with water, and 2) the target product (ethanol) is lost during the purge cycle, and (relative) product recovery. Hinders the dehydration process. Since the ethanol dehydration process is a process swing adsorption method, the goal of any product development is to improve both adsorption of adsorbate (selectivity of water) and reduction of adsorption of the target product (ethanol). It is done.

  Another application of the molecular sieve formulation disclosed herein is the drying of cracked gas, more specifically, drying of the gas stream by contacting the pyrolytic hydrocarbon gas stream with the zeolite blend. In such processes, if water is not removed, hydrocarbon hydrates are formed, which precipitate as solids, clog pipelines, freeze valves and regulators, and rectification towers (unsaturated hydrocarbons). Clogging of cracked gas for recovery) may occur. For example, during conventional ethylene separation, water present in the feed stream can often form hydrates with the ethylene due to the low temperature or high pressure of the feed stream. These hydrates can accumulate to form solids, making it impossible to pass the required vaporous or liquid charge through the column.

  One way to solve this problem was to use a desiccant. However, the desiccant has a drawback that its lifetime is short. Another method of drying the cracked gas is to use a zeolite adsorbent. However, due to the size of the zeolite crystals, it must be mixed with the binder material to form a mass before being used in this drying process. The problems associated with the use of these binders have already been described.

  A particularly effective zeolite useful for dehydration from ethanol: water mixtures and drying of cracked hydrocarbons is hydrophilic zeolite 3A. Zeolite 3A is particularly effective at adsorbing water due to the pore size of the zeolite, which allows the passage of water molecules but restricts the passage of larger hydrocarbon molecules including ethanol. While zeolite 3A is a particularly useful zeolite for this and related processes, other zeolites can be used for other processes, such as the use of zeolite 5A for iso / normal paraffin separation.

  It has been unexpectedly discovered that the zeolite, preferably zeolite A, especially zeolite 3A, should be ion exchanged with potassium to increase the water adsorption capacity of the zeolite. The degree of ion exchange with potassium ions often varies depending on the end use of the molecular sieve formulation containing the zeolite.

  In one example, when zeolite 3A is used for water adsorption from an ethanol feed stream, it is necessary to balance the ability of the adsorbent to adsorb water against its ability to co-adsorb ethanol from the feed stream. . Industry standards generally suggest that ethanol adsorption levels should be kept below 2 mmol / g, measured at around 32 mbar and 298K. It is unexpectedly found that when water adsorption is balanced against ethanol adsorption, the potassium ion exchange of zeolite 3A needs to be more than 30%, preferably more than 40%, particularly preferably more than 50%. It was done. If the potassium ion exchange of zeolite 3A used for the adsorbent is higher than 65%, the amount of co-adsorbed ethanol may be further reduced, but at this ion exchange level, the water adsorption capacity of the adsorbent decreases sharply. .

  Also, the degree of ion exchange of the zeolite with potassium ions needs to be controlled to provide proper pore closure of the adsorbent so that the selectivity of water adsorption for polar hydrocarbon species inside the feed gas can be controlled. . The pore size can be controlled by limiting the degree of zeolite potassium ion exchange, and in one example, the results are approximated by the heat of adsorption generated by exposing the adsorbent to a blend of water and liquid methanol. Can be made.

  It is necessary to balance total water adsorption capacity and pore closure (selectivity) so that the most preferred adsorbent for the intended application is obtained. Thus, for commercial processes, the best balance of water adsorption capacity for adsorption of polar materials such as ethanol requires that the potassium ion exchange rate of the zeolite be 45-65%.

  The remaining cations of the zeolite may be sodium ions, or other alkalis that do not interfere with the ion exchange of the zeolite by the adsorption of water by the zeolite 3A or the passage of the hydrocarbon stream through the zeolite 3A blend or You may carry out by alkaline-earth metal ion.

In one specific embodiment, the selected zeolite has a low silica, SiO ₂ : Al ₂ O ₃ ratio of less than 50, alternatively less than 20, more preferably less than 10, even less than 5, optionally as low as 1. It is a hydrophilic zeolite. In order to produce zeolites that are particularly effective for the adsorption of polar substances, especially water, it is useful to reduce the SiO ₂ : Al ₂ O ₃ ratio of this type of zeolite. Methods for producing low silica zeolite are well known. Since low silica zeolite is hydrophilic as defined in Example 4 below, it is more effective as an adsorbent for water from hydrocarbon / water mixtures than, for example, high silica zeolites commonly used in catalytic reactions. is there. (Zeolite blends useful for such catalytic reactions are not disclosed herein. Furthermore, the disclosed zeolite blends are not generally utilized for this type of catalytic reaction.) Also, such low silica zeolites are Reduce the possibility of producing green oil and coke in the process.

  The use of this type of zeolite requires that the individual zeolite crystals be joined together in the form of a tangible product that reduces the pressure drop during the adsorption process. However, conventionally, the binder material used did not increase the adsorption capacity and selectivity of the zeolite. Indeed, conventional binder materials generally reduced the adsorption capacity of zeolites, resulting in the production of undesirable oligomers and polymers (green oil and coke). Binder materials conventionally used for zeolites generally include clay products such as kaolin, palygorskite-type minerals, particularly attapulgite, and smectite-type clay minerals such as montmorillonite or bentonite. These clay products have been selected for various reasons including their hydrophilicity. These clay binders have been used alone or as a mixture of two or more different types of clay binders.

  The above clay binders, particularly attapulgite, often have a high metal content. Such metals can cause carbon polymerization at acid sites on the clay binder during use in the process disclosed herein. This often results in the production of coke and green oil and tends to shorten the useful life of the zeolite blend. Such conventional zeolite / clay binder bulk materials showed a high incidence of coking phenomena in the presence of unsaturated hydrocarbons when used in adsorption or separation processes. One advantage of the zeolite formulations disclosed herein is that hydrocarbon polymerization is reduced and coke and green oil production is reduced, thus increasing the estimated useful life of the adsorbent.

  It has been unexpectedly discovered that improved performance of the adsorbent material can be obtained when the binder material used is a silicon-based material, especially when the silicon-based material is hydrophobic. For the purposes of this disclosure, whether a silicon-based material is “hydrophilic” or “hydrophobic” is based on the definition contained in Example 4.

In one embodiment, the molecular sieve formulation contains a low silica zeolite with a low SiO ₂ : Al ₂ O ₃ ratio as defined herein with a silicon-based material, preferably colloidal silica, or in a less preferred embodiment, siloxane. To do. Here, it is preferable that the silicon-based material is subjected to a treatment for making part or substantially all of its surface hydrophobic, if necessary. The silica can be treated to produce a hydrophobic surface according to methods well known in the prior art. For example, this treatment can be performed by treating the silicon-based material with a hydrophobizing agent, for example, a hydrolyzable silicon compound having at least one alkoxy group in the molecule or a hydrolyzate thereof.

A preferred hydrophobic silicon-based material used as a binder is colloidal silica in one embodiment. Colloidal silica is generally a suspension of amorphous (amorphous) non-polar, typically spherical silica particles suspended in a liquid phase. One example is Ludox ^™ manufactured by Grace Davison, which has a colloidal silica pH of 10. The silica concentration in the colloidal silica, the silica ratio of SiO ₂ : Al ₂ O ₃ , the particle size of the silica particles, and the surface area of the silica particles can vary depending on the colloidal silica.

  In another example, although not preferred, the silicon-based material is a hydrophobic siloxane-based material. Specific examples of the siloxane-based material may include, for example, dimethylsiloxane, silsesquioxane or a mixture thereof, or other well-known siloxane-based materials. One specific example of a siloxane-based material is IE-2404 emulsion from Dow Corning, which contains 40-70% dimethylsiloxane along with methylsilsesquioxane and x-octylsilsesquioxane.

  The inventors have found that a molecular sieve formulation produced using colloidal silica is better than conventional adsorbents in which zeolite is bound using a clay binder such as attapulgite, and the binder comprises a siloxane-based material. It was unexpectedly discovered to produce a better performing adsorbent. In addition, the molecular sieve compound using colloidal silica material as a binder has water adsorption capacity, water / ethanol adsorption selectivity, leakage time, length of unused bed (LUB), and pore distribution coefficient (pore distribution). It was unexpectedly discovered that the coefficient) (defined later) shows better performance. A comparison of the performance of molecular sieve formulations using colloidal silica binders versus adsorbent materials using conventional attapulgite binders or siloxane-based materials is shown in the various examples and figures described below.

  Once a suitable zeolitic material for a given application is selected, such as a low silica hydrophilic zeolite A, preferably zeolite 3A, for water adsorption, it is treated with a hydrophobic silicon-based binder, preferably colloidal silica, or In a less preferred embodiment, it is mixed with a siloxane-based material in the presence of water. Thereafter, the hydrophilic zeolite 3A powder and the hydrophobic silicon-based binder are mixed together with water. The amount of hydrophobic silicon-based binder utilized for the hydrophilic zeolite is in the range of 20-30% by weight, or 2-20% by weight, or even 2-10% by weight, based on the final adsorbent formulation. It may be within the range.

  It has been unexpectedly discovered that an improved adsorbent formulation can be produced when a seed (core material) produced by the granulation seed method is used in the production of the formulation. The composition of the seed produced by this granulation method comprises, in one preferred method, zeolite, in particular zeolite 3A, and a clay binder. Depending on the method used to produce the molecular sieve formulation, certain silicon-based binders can also be included in the seed. However, the amount of this silicon-based binder material present in the seed is relatively low, generally less than 10%.

  The use of clay-based materials in the seeding process has been found to be particularly advantageous for increasing production yields and / or production yields compared to adsorbent formulations made without seeds. . In this method, the seeds or nuclei of the adsorbent product are formed using clay and zeolite to mimic an agglomeration process. Typically, in this embodiment, the seed comprises 0.5-25% by volume of the agglomerated adsorbent formulation. The total amount of clay present in the formulation in this case should not exceed 5%, preferably 3% or less, based on the dry weight of all components of the adsorbent formulation. The silicon binder is preferably less than 1 part of the clay binder with respect to 5 parts of the silicon binder, and more preferably less than 1 part of the clay binder with respect to 20 parts of the silicon binder. The minimum amount of clay binder present in the adsorbent formulation is 0.5% on a dry weight basis.

Conventional adsorbed products have utilized many types of clay materials as binder materials, including kaolin, palygorskite-type minerals, especially attapulgite, smectite-type clay minerals such as montmorillonite and bentonite, halloysite and sepiolite. Any of these clay materials can be used as the seed clay component, and other activated clay materials such as Actigel ^™ can be used.

  In another aspect, rather than using a clay material to form the adsorbent seed binder, it is also useful to use a silicon-based material as described above as a zeolite binder to form the adsorbent. There are cases. The amount of silicon-based material used to form the seed, as well as the total volume of the seed made from the silicon-based material, is similar to that for the clay materials described above.

  In general, the process for producing a molecular sieve formulation with improved adsorption performance characteristics of the present invention using seeds is as follows: zeolite with clay binder material (and optionally a small amount of silicon-based binder); Seeds are prepared by blending at an appropriate ratio of 5-20% clay to 80-95% zeolite on a dry weight basis. The seed formed forms the core of the adsorbent formulation, which seed particles make up 0.5-25% by volume of the agglomerated particles. Preferably, the amount of seed particles should be kept as low as possible within a range that allows the intended granulation effect. Unexpectedly, agglomerated seed particles produced using only silicon-based binders with zeolites used to initiate the agglomeration process generally provide the controlled particle growth required for commercial use of adsorbents. It has been found that it is not effective to occur, yields are reduced, production time is increased, and the production method is more inefficient.

  Following the preparation of a seed material containing a clay binder and an appropriate amount of zeolite (and optionally a small amount of a silicon-based binder), a mixture of a preferably hydrophobic silicon-based binder and preferably a hydrophilic zeolite is combined with this seed and an appropriate amount. Mix until sized adsorbent particles are formed. The resulting product can be shaped into beads, pellets, tablets and other conventional product shapes.

  An important additional manufacturing step customary for the production of shaped zeolite adsorbents is the introduction of plasticizers, pore formers and / or temporary binders, in particular cellulose-containing materials, in particular methylcellulose. Materials such as polysaccharides, polyvinyl alcohol, starch, and other mixtures may also be used as a substitute for methylcellulose as a plasticizer as long as they are water soluble. For example, in US Pat. No. 6,458,187, which describes a molded body made from a zeolite and a siloxane-based binder, one essential component of the molded body is a plasticizer in an amount of 5-40% by weight. It was used as a methylcellulose.

  In contrast, the addition of methylcellulose or similar plasticizers to the adsorbent formulations disclosed herein can adversely affect the production of the adsorbent formulation itself and the properties of the produced adsorbent formulation. It was discovered unexpectedly. Specifically, the use of methylcellulose in the adsorbent formulation according to the present invention adversely affects the final pore structure of the adsorbent for certain applications and is as useful as that of the preferred embodiment. It was unexpectedly discovered to produce a non-adsorbent formulation. Furthermore, the use of methylcellulose has been found to reduce the overall production yield. Furthermore, the presence of methylcellulose has been found to result in products with low sphericity and / or form factor. Such products are undesirable in that the pressure drop in the packed bed adsorption process is increased compared to formulations formed from the same size with high sphericity and / or shape factor. Accordingly, in a preferred embodiment, cellulosic plasticizers, particularly methylcellulose, are not utilized in the production of the preferred molecular sieve adsorbent formulation. In a more preferred embodiment, it is an important element of the production process that such plasticizers, especially including cellulosic plasticizers such as methylcellulose, are not used in the production process of the adsorbent formulation of the present invention.

Certain types of pore formers such as sawdust or other comminuted organic materials may be utilized, but are not an essential element of the adsorbent disclosed herein.
After the formed product is shaped into a suitable shape, it can be hydrothermally treated (or calcined) to maintain the pore size, while maintaining the ability to adsorb water from the feed stream, for purposes such as ethanol. Reduce to a size that eliminates the hydrocarbons that do. Unexpectedly, it has been discovered that the calcining temperature of the formed adsorbent formulation is important with respect to the properties of the adsorbent formulation. In prior art, such as US Pat. No. 6,458,187, calcining must be performed at a temperature within a narrow temperature range from 180 ° C. to 280 ° C. in order to maintain the maximum compressive strength of the adsorbent product. I was taught. US Pat. No. 6,458,187, when calcined at a temperature higher than 280 ° C., causes release of methyl groups from the siloxane-based binder used in the adsorbent product, and the final compressive strength of the product is I was determined to be weak.

  In contrast, to produce a shaped adsorbent formulation that exhibits the adsorption properties required for the methods disclosed herein, calcining is at least in the range of 500 ° C to 700 ° C, preferably 600 ° C to 650 ° C. It was unexpectedly discovered that it had to be done. Nevertheless, it is important that the calcining temperature does not exceed 700 ° C., preferably 675 ° C. or less. By keeping the calcining temperature range within the range described here, effective and useful adsorption properties are exhibited by the adsorbent formulation produced by the method disclosed herein. For evidence of the importance of calcining temperature, see FIG. 7 utilizing 3A zeolite with 50% potassium ion exchange rate (see comparative example 7).

  The molecular sieve adsorbent formulation of the present invention exhibits a preferred pore structure. The analysis of the pore structure can be determined by measurement by mercury porosimetry (mercury intrusion method). Using data obtained from analysis by mercury porosimetry, total particle porosity, median pore diameter, pore volume in the range of 0.1 to 1.0 μm, and pore distribution A coefficient can be obtained.

The adsorbent formulation of the present invention preferably has a total particle porosity in the range of 32% to 40%.
The median pore diameter is preferably at least 0.25 μm, more preferably more than 0.4 μm, and most preferably more than 0.5 μm. The maximum value of the median pore diameter is not particularly specified, but is actually 1.5 μm.

  It is also preferred that the pores are of an appropriate size, and the preferred pore size is in the range of 0.1-1 μm. The pore distribution can be obtained by computer calculation of “pore distribution coefficient”. In this document, the pore distribution coefficient is defined by the following equation.

((A * B) + (C * D) + (E * F)) * G × 1000 = pore distribution coefficient where
A => 1 μm pore (ml / g)
C = <0.1 μm pore (ml / g)
E = <1 μm and> 0.1 μm pores (core fraction) (ml / g)
G = total pore volume (ml / g)
B = A / G
D = C / G
F = E / G.

  Using the pore distribution coefficient defined above, the adsorbent formulation of the present invention preferably has a pore distribution coefficient of greater than 40, preferably greater than 60. A high pore distribution coefficient of over 100 is not detrimental, but may be impractical or unnecessary to produce an efficient adsorbent product. A performance comparison of a sample of adsorbent particles of the composition of the present invention versus a conventional adsorbent is shown, for example, in Table 4. It should be noted that the comparative adsorbent has a pore distribution coefficient of less than 40, while the coefficient when using the adsorbent of the present invention is greater than 40 and generally greater than 60.

  To examine the performance of various molecular sieve formulations for removing water from a hydrocarbon feed stream, the leakage time, MTC (mass transfer coefficient), pore distribution coefficient, unused bed length (LUB) and selectivity were determined. The various standards included are important standards as disclosed in this document. Furthermore, the relationship between the pore distribution coefficient of various adsorbents and LUB is shown in FIG.

Products produced by the methods disclosed herein exhibit improved water adsorption rates. The adsorption rate can be determined using several different methods. For example, the water adsorption rate of a material can be determined by fitting the temperature profile data to a first order decay function given by: f = a * e ^−kt . The slope “−k” of this curve represents the water adsorption rate of the material.

Another method of measuring the adsorption rate of a molecular sieve adsorbent formulation can measure the amount of material adsorbed over a period of time.
In yet another method of measuring the adsorption rate, the length of the mass transfer zone of the formulation under certain conditions can be compared to that of a conventional zeolite adsorbent formulation. The shorter the mass transfer zone, the higher the adsorption rate.

Finally, the diffusivity can be determined directly for a certain gas or liquid. The higher the diffusion rate, the higher the adsorption rate.
Unexpectedly, by using the adsorbents disclosed herein and the method of manufacturing the same, an improved water adsorption rate can be obtained regardless of which method was used to measure the adsorption rate. It was. This improvement is at least 10% and can be as high as 350% compared to products containing conventional attapulgite clay binders.

  It has also been unexpectedly found that even if the amount of preferably hydrophobic silicon-based binder used in the adsorbent is reduced, the adsorption rate is increased compared to conventional adsorbent products using conventional clay binders. It was. This improvement is at least 10%, and in many cases is as great as 30% or more. This improvement is particularly apparent when a granulated seed process, preferably using a clay binder in the seed, is used to produce the adsorbent product.

  It is also unexpected that the adsorbents disclosed herein produced by the method disclosed herein exhibit improved crush strength and hysteresis values superior to those prepared using conventional clay binders. Admitted.

  A further unexpected finding is that by using a silicon-based material that is preferably hydrophobic as the binder material, undesired oligomers and polymers are produced when the zeolite / silicon-based adsorbent blend is used as a dehydrating agent. This is a significant reduction. In addition, due to the reduced production of such oligomers and polymers, the estimated useful life of the zeolite blend is also increased.

These improvements are particularly noticeable when the adsorbent is formed using a seed, preferably formed by a granulation seed method using a clay binder.
In addition, the use of the adsorbent disclosed herein reduces the need for regeneration and lowers the regeneration temperature, resulting in further cost savings.

In addition, the selectivity of the substance to be adsorbed can be improved.
These improvements are demonstrated by the following examples. In these examples, the sample material is tested in the form used for the molecular sieve formulation.

Example 1
To compare the performance of various adsorbents, and an unexpected zeolite formulation comprising a seed preferably utilizing a hydrophilic zeolite, preferably a hydrophobic silicon-based binder, and in some embodiments a clay binder. In order to show selectivity, samples of various adsorbents having different compositions are prepared or obtained. These compositions are compared to show their selectivity for removal of water from an ethanol stream using a method.

  Dry the selected adsorbent sample at 240 ° C. overnight. The sample is cooled to room temperature in a desiccator. Twenty grams of this sample is placed in a 50 ml two-necked round bottom flask. Insert a thermocouple into the flask through the thermocouple inlet. The flask is stoppered and then placed in a water bath maintained at 30 ° C. The sample is then allowed to equilibrate for 15 minutes to achieve temperature equilibrium. Using a glass syringe, 25 ml of the test solution (90/10 mixture of ethanol / water) is withdrawn from the master container that has also been equilibrated to 30 ° C. The test solution is then poured into the flask and the resulting temperature profile is collected for 120 seconds. The value of maximum temperature rise indicated for each material during this period is then used to calculate the selectivity (α) for that material by using the following equation: α = Tmax−Tintial. Tmax: maximum temperature, Tintial: initial temperature.

  The basic premise of this test procedure is that the greater the selectivity of the material to water, the higher the temperature rise in the adsorption process. A material exhibiting low selectivity is considered to exhibit a lower temperature rise due to the greater amount of ethanol co-adsorption that blocks the active sites of the zeolite. Data from tests on various samples are collected and shown in various tables and figures. Table 1 and FIG. 1 show the maximum increase in temperature during the test process. The maximum temperature rise may be indicated at different times during the test process for each sample.

  According to this test, the “strong” separation factor is a value of 30 ° C. and no separation at 0 ° C. The defined threshold for “non-selective material” is less than 10 ° C. The determination of the threshold of 10 ° C. for “non-selective materials” was determined after consideration of materials that were known for their selectivity when tested alone or lacked selectivity. For example, in the case of hydrophobic materials such as high silica ZSM-5 and pure silica (such as colloidal silica HS-30 from WR Grace), low selectivity results are obtained. In addition, a number of hydrophilic materials have been tested and their composition will be described later.

Not surprisingly, pure zeolite 3A, which is a known hydrophilic material, exhibits high water selectivity. Actigel ^™ 208 made of attapulgite material exhibits a high selectivity of 18 ° C. Another sample exhibiting a selectivity coefficient higher than 10 ° C. is a blend of 10% colloidal silica (HS Grace HS-30) and 90% zeolite 3A (Zeochem) (referred to as I-1), organic A blend of siloxane emulsion (IE-2404 from Dow Corning) and zeolite 3A (Zeochem), with the amount of siloxane material being 5% of the blend and the amount of zeolite 3A being 95% of the blend. (Referred to as I-2), zeolite 3A, various amounts of siloxane emulsion (IE-2404), and seeds formed by granulation methods of various volumes (wherein the seeds are zeolite and various amounts) Containing various clay binders) (referred to as I3 to I8).

The tested materials are described below and a comparison of their selectivity is shown in Table 1 and FIG. (For purposes of this disclosure, a material is “selective” for water adsorption in a water / ethanol mixture if the temperature rise is greater than 10 ° C. when tested using the described method. On the other hand, if the temperature rise is less than 10 ° C., the material is “non-selective”.)
Sample (test specimen) description:
Invention Example Sample 1 (I-1)
This material consists of 10% colloidal silica (HS-30, manufactured by WR Grace) and 90% 3A zeolite powder, manufactured by Zeochem. The material is in the form of spherical particles.

Invention Example Sample 2 (I-2)
This material is a blend of siloxane-based binder (IE-2404) manufactured by Dow Corning containing dimethylsiloxane, methylsilsesquioxane and n-octylsilsesquioxane in zeolite 3A powder (Zeochem). The amount of siloxane-based binder is 5%, and the amount of zeolite 3A powder is 95%.

Comparative Example Sample 1 (C-1)
This material is a blend of 10% binder and 90% 3A zeolite powder made by Zeochem. The binder is 50/50 blend of colloidal silica (HS-30) and Actigel ^TM 208 clay (manufactured by Active Minerals). It is a thing. The material is in the form of spherical particles.

Comparative sample 2 (C-2)
This material consists of 10% Actigel ^™ 208 attapulgite clay from Active Minerals and 90% 3A zeolite powder from Zeochem. The material is in the form of spherical particles.

Comparative Example Sample 3 (C-3)
It is made by Ceca (the parent company is Arkema). This material consists of 20% attapulgai and 80% 3A zeolite powder. The material is in the form of spherical particles.

Comparative sample 4 (C-4)
Made by Zeochem. This material consists of 20% attapulgai clay (manufactured by Active Minerals) and 80% 3A zeolite powder. The material is in the form of spherical particles.

Comparative Example Sample 5 (C-5)
Made by WR Grace. This material consists of 20% attapulgai clay and 80% 3A zeolite powder. The material is in the form of spherical particles.

Comparative Example Sample 6 (C-6)
Made by Hengye. This material consists of 20% attapulgai clay and 80% 3A zeolite powder. The material is in the form of spherical particles.

Comparative Example Sample 7 (C-7)
Made by Zeochem. This material is zeolite 3A powder.
Comparative Example Sample 8 (C-8)
Made by WR Grace. This material is a colloidal silica solution with a SiO ₂ content of 30%. Prior to testing the colloidal silica material, it was dried to 80 ° C. for 1 hour, 110 ° C. for 1 hour, 250 ° C. for 1 hour, and 550 ° C. for 1 hour to form a SiO ₂ powder.

Comparative Example Sample 9 (C-9)
Made by Zeochem. This material is a ZSM-5 zeolite powder with a high Si / Al ratio (600). This material is in extruded form.

Comparative Example Sample 10 (C-10)
Actigel ^™ 208 (manufactured by Active Minerals). This material is attapulgite clay powder.

Comparative Sample 11 (C-11)
Made by UOP. This sample contains 20% clay and 80% 3A zeolite powder. This sample is in an extruded form.

Comparative Example Sample 12 (C-12)
Minugel ^TM MB (manufactured by Active Minerals). This material is attapulgite clay powder.

Invention Example Sample 3 (I-3)
This sample consists of 5% siloxane-based product (IE-2404 from Dow Corning), 95% 3A zeolite powder from Zeochem (amount determined without considering the amount of seeds), and seeds. % Occupies 15% of the total adsorbent. This seed consists of 90% 3A zeolite powder from Zeochem and 10% Actigel ^™ 208 from Active Minerals.

Invention Example Sample 4 (I-4)
This sample consists of 5% siloxane-based product (IE-2404 from Dow Corning), 95% 3A zeolite powder from Zeochem (amount determined without considering the amount of seeds), and seeds. % Occupies 30% of the total adsorbent. This seed consists of 90% 3A zeolite powder from Zeochem and 10% Actigel ^™ 208 from Active Minerals.

Invention Example Sample 5 (I-5)
This sample consists of 5% siloxane-based product (IE-2404 from Dow Corning), 95% 3A zeolite powder from Zeochem (amount determined without considering the amount of seeds), and seeds. % Occupies 15% of the total adsorbent. This seed consists of 80% 3A zeolite powder from Zeochem and 20% Minugel MB from Active Minerals.

Invention Example Sample 6 (I-6)
This sample consists of 5% siloxane-based product (IE-2404 from Dow Corning), 95% 3A zeolite powder from Zeochem (amount determined without considering the amount of seeds), and seeds. % Occupies 15% of the total adsorbent. This seed consists of 90% 3A zeolite powder from Zeochem and 10% halloysite from Active Minerals.

Invention Example Sample 7 (I-7)
This sample consists of 5% siloxane-based product (IE-2404 from Dow Corning), 95% 3A zeolite powder from Zeochem (amount determined without considering the amount of seeds), and seeds. % Occupies 15% of the total adsorbent. This seed consists of 90% 3A zeolite powder from Zeochem and 10% Sepiolite (Pansil-400) from Tolsa.

Invention Example Sample 8 (I-8)
This sample consists of 10% siloxane-based product (IE-2404 from Dow Corning), 90% Zeochem 3A zeolite powder (amount determined without considering the amount of seeds), and seeds, % Occupies 15% of the total adsorbent. This seed consists of 90% 3A zeolite powder from Zeochem and 10% Actigel ^™ 208 from Active Minerals.

  From Table 1 and FIG. 1, pure colloidal silica is hydrophobic and therefore has poor water selectivity by itself, but when blended with zeolite 3A powder to form I-1, the compound material is It is clear that the selectivity value for water in a water: ethanol mixture is almost as high as when a conventional clay binder, which is hydrophilic, is used alone. It is also clear that the blend (I-2) of siloxane-based binder (IE-2404) and zeolite 3A also results in an adsorbent blend having a high selectivity value. Furthermore, when a granulated seed formed using a clay binder is used in the production of an adsorbent blend containing colloidal silica and 3A zeolite, the adsorbent blend also has a high selectivity value. It is also apparent that Any other material formulation, including some combination of hydrophilic 3A zeolite and conventional attapulgite clay binder, may be a combination of hydrophilic zeolite 3A of the present invention and a hydrophobic silicon-based binder or siloxane-based binder, or Furthermore, it did not show the selectivity within the range exhibited by the adsorbent formulation containing the seed.

Example 2
In order to compare the performance of various materials against the production of undesirable hydrocarbons, commonly referred to as “coke”, which commonly occurs during certain adsorption processes, coking tests (coke generation tests) are performed on various samples. This test is for seeds formed with a zeolite and clay binder in a blend of a hydrophilic zeolite and a hydrophobic silicon-based binder or an adsorbent formulation containing a hydrophobic silicon-based binder and a hydrophobic zeolite. It has been demonstrated that the use of has reduced coke generation during standard coking tests compared to other samples.

  Weigh 0.1 grams of each sample, dry overnight, and place in desiccator. The sample is exposed to a gas stream containing 4% by volume of reactive diene (1,3-butadiene), the balance being nitrogen (the flow rate of the gas stream is 60 ml / min) at 450 ° C. for 12 hours. This sample is monitored for the tendency to form green oil that will result in carbon deposition called coke.

  A test specimen is selected from the sample of Example 1. The results are shown in Table 2 and FIG.

  As is apparent from the results shown in Table 2 and FIG. 2, a composition obtained by mixing hydrophilic zeolite 3A with a hydrophobic colloidal silica binder or siloxane-based binder, or a seed formed using a zeolite and a clay binder. The adsorbent formulation containing a hydrophobic silicon-based binder and a hydrophobic zeolite showed better performance than any of the comparative clay binders due to the low total coke production during the test period. . It is also clear that the use of seeds consisting of hydrophilic 3A zeolite and a conventional clay binder in the production of molecular sieve formulations does not adversely affect the butadiene reactivity of the adsorbent formulation.

Example 3
In order to compare the water adsorption rate of various materials, as described above, an adsorption test is performed to compare the dynamic rate of water adsorption of the test material by applying the temperature profile data to the first-order decay function. The selected product is selected from the sample group used in Example 1.

  The sample to be tested is dried at 240 ° C. overnight. The sample is cooled to room temperature in a desiccator. 20 grams of this sample is placed in a 50 ml two-necked round bottom flask. Insert a thermocouple into the flask through the thermocouple inlet. The flask is stoppered and then placed in a water bath maintained at 30 ° C. The sample is then allowed to equilibrate for 15 minutes to achieve temperature equilibrium. Using a glass syringe, 25 ml of the test solution (90/10 mixture of ethanol / water) is withdrawn from the master container that has also been equilibrated to a temperature of 30 ° C. The test solution is then poured into the flask and the resulting temperature profile is collected. The data is then analyzed by fitting a first order attenuation model to the resulting temperature profile as described above. The slope of the decay curve shows the apparent water mass transfer. The results are shown in FIG.

  As is evident from the test results shown in FIG. 3, the best disclosed water adsorption dynamic rate is that shown by I-1. The high exotherm of this sample and the steepness (steepness) of the thermal front (thermal front) indicate very advantageous and quick water adsorption in the presence of ethanol. This uptake (adsorption) is surprisingly 3-4 times higher than the best conventional adsorbents, indicating excellent water uptake properties.

Example 4
A test has been developed to classify whether a material is “hydrophobic” or “hydrophilic”. The test consisted of taking approximately 10 grams of test sample and drying it at 230 ° C. for 4 hours. The material to be tested is in particle form. In the case of beads, the sample passes through a 4 mm × 4 mm sieve. In the case of extrudates, the diameter is 1/8 inch (3.1 mm). The sample material is tested in the same form used for the molecular sieve formulation. The dried sample is then weighed and placed in an air stream and hydrated to 1 atm, 20 ° C. and 80% relative humidity. The weight gain obtained by water adsorption is then recorded and plotted to determine the maximum water adsorption capacity as well as the relative water adsorption rate.

  Samples are evaluated for total water adsorption capacity as well as relative adsorption rate. In order to determine the ultimate adsorption capacity, the final weight increase after 7.5 hours is determined. The relative water adsorption rate of the material is also calculated after 60 minutes. If a sample's water adsorption capacity after 7.5 hours is less than 5.5% (weight) and the relative water adsorption rate after 60 minutes is less than 0.05% (weight) per minute, the sample is “hydrophobic. ”. From this analysis, the zeolite sample (C-7) and the clay binders used alone (C-10 and C-12) show adsorption properties consistent with “hydrophilic” materials, whereas the silica binder (C— 8) shows the property of “hydrophobicity”.

  These test results are shown in Table 3 and FIGS.

Example 5
Table 4 shows the results of collecting and analyzing mercury porosimetry data for various adsorbents in order to compare the influence of the binder system on the pore structure of the adsorbent. Standard mercury intrusion experiments are performed using a Micromeritics Autopore IV 9500. The data is analyzed for the total porosity of the adsorbent, the median pore size (median pore diameter), and the pore distribution coefficient (PDC) defined as:

((A * B) + (C * D) + (E * F)) * G × 1000 = pore distribution coefficient where
A => 1 μm pore (ml / g)
C = <0.1 μm pore (ml / g)
E = <1 μm and> 0.1 μm pores (core fraction) (ml / g)
G = total pore volume (ml / g)
B = A / G
D = C / G
F = E / G.

Example 6
To examine the performance of the adsorbent to remove water from the hydrocarbon stream, a dynamic water adsorption test is performed on various samples as shown in Table 5. The test consists of packing the adsorbent to be tested into a 2 inch diameter adsorption column to a height of about 19 cm. A carrier gas containing 2100 ppmV water vapor is then passed through the adsorbent column at 25 ° C. and 50 psi. Collect and analyze the resulting leakage curves.

  From this dynamic evaluation, useful equilibrium and dynamic information of adsorption can be derived. One such useful dynamic criterion is the unused bed length, or LUB. LUB is defined as half of the mass transfer zone spread. This length quantification describes the shape of the breakthrough front as it moves through the adsorbent packed column.

  For the calculation, the feed mixture (in this case water and air) is introduced into the adsorbent packed column. When the feed stream is continuously fed to the packed bed (bed), the adsorbate (water in this test) becomes saturated in the packed bed. The saturated portion of the packed bed is called the equilibrium zone and its concentration corresponds to the adsorption capacity of the adsorbent for the adsorbate at the feed conditions. The portion of the packed bed where the feed is still equal to the feed concentration is called LUB. An intermediate zone exists between the two, and this zone is called a mass transfer zone because mass transfer from the fluid phase to the adsorption phase takes place there. When the forefront of this mass transfer zone reaches the outlet, the packed bed is said to be “leakage”.

  If the concentration of water in the packed bed effluent is plotted as a function of time, a curve is obtained. From this curve, LUB can be calculated by the following equation.

Where
LUB = unused bed length L = length of packed bed (height)
t _m = midpoint time, ie, time when X _effluent = X _feed / 2 t _b = leakage time, ie, time when X _effluent = X _b X = concentration of water in the feed stream
effluent: Outflow, feed: Supply flow, b: Leakage, m: Midpoint.

  The higher the pore distribution coefficient and the lower the LUB, the more effective the adsorbent is as an adsorbent. FIG. 6 shows the result of comparison of the pore distribution coefficient with respect to LUB for the various adsorbents tested in the examples.

Example 7
To study the effect of calcining temperature on the adsorption of molecular sieves, water and methanol adsorption using zeolite 3A from comparative sample C-7 with 50% potassium ion exchange calcined at various temperatures Perform the test. The zeolite 3A sample is dried by heating to 250 ° C. using a temperature rising rate of 35 ° C./hour, and then kept at 250 ° C. overnight. The sample is then sealed. A certain amount of this sample is taken out and calcined at different temperatures one by one for 90 minutes. The temperatures used for calcining the samples are 300 ° C, 400 ° C, 500 ° C, 600 ° C, 650 ° C, 700 ° C and 750 ° C. After each calcination for 90 minutes, the sample is cooled to a temperature that can be safely handled in a desiccator.

  Each sample is analyzed for temperature rise when 10 g of sample is exposed to 25 mL of methanol at 30 ° C. Each sample is also analyzed for equilibrium water adsorption capacity at 50% relative humidity. The test results are shown in FIG.

  As is apparent from this figure, the sample showing an allowable methanol adsorption capacity of 20% or less was calcined at a temperature in the range of 500 ° C. to 750 ° C. More acceptable water adsorption is shown at calcining temperatures in the range of 650 ° C to 750 ° C.

  Although the present invention has been described in detail above, it will be clearly understood that this disclosure is not to be construed as any limitation on the present invention.

Claims (18)

Comprising the following components, gases or liquids supply flow dehydrating molecular sieve formulation:
Zeolite;
Hydrophobic silicon-based binder; a both agglomerated seed with the zeolite and the silicon-based binder to form a and molecular sieve formulation, seeds containing the zeolite and the clay binder;
Wherein the seeds form the core or core of the molecular sieve formulation, and
The amount of the clay binder present in the molecular sieve formulation accounts for 0.5% to 5% of the formulation by weight. 2. The molecular sieve according to claim 1, wherein the zeolite is a hydrophilic zeolite selected from the group consisting of zeolite A, zeolite X, zeolite Y, zeolite ZSM-5, zeolite β, synthetic mordenite, and blends thereof. Formulation. SiO ₂ / Al ₂ O ₃ ratio of the zeolite is less than 50, according to claim 1 or molecular sieve formulation according to 2. The hydrophobic silicon-based binder, molecular sieve formulation according to any one of 請 Motomeko 1-3 which accounts for 2% to 30% by weight of the molecular sieve formulation. The molecular sieve compound according to any one of claims 1 to 4, wherein the hydrophobic silicon-based binder contains colloidal silica. The molecular sieve formulation according to any one of claims 1 to 4, wherein the hydrophobic silicon-based binder comprises a siloxane-based material. The molecular sieve formulation according to any of claims 1 to 6, wherein the zeolite is ion exchanged with potassium ions in a proportion of more than 30%. Coke production rate of less than 5.0 × 10 ⁻⁹ mmol / g / min when the formulation is exposed to a 450 ° C. nitrogen stream containing 4% by volume of 1,3-butadiene at a flow rate of 60 m / min. The molecular sieve formulation according to any one of claims 1 to 7, wherein The median pore diameter of the formulation is at least 0.25 micron m, molecular sieve formulation according to any one of claims 1 to 8.   The molecular sieve formulation according to any of claims 1 to 9, wherein the total particle porosity of the formulation is 32% to 40%. The pore distribution coefficient of the formulation is at least 4 0, molecular sieve formulation according to any one of claims 1 to 10.   The molecular sieve formulation according to any of claims 1 to 11, wherein the seeds comprise 0.5 to 25% by volume of the molecular sieve formulation.   13. A molecular sieve formulation according to any preceding claim, wherein the selectivity is at least 10 ° C when the formulation is exposed to a 90% / 10% ethanol / water mixture for 120 seconds at 30 ° C. The manufacturing method of the molecular sieve compound in any one of Claims 1-13 including the following processes:
Preparing or obtaining a zeolite;
Preparing or obtaining a hydrophobic silicon-based binder;
Mixing the zeolite and the hydrophobic silicon-based binder to form a mixture;
Preparing a seed comprising a clay binder and said zeolite;
A molecular sieve formulation is formed from the mixture using the prepared seed; and the formed molecular sieve formulation is calcined at a temperature of 500 ° C to 700 ° C to produce a molecular sieve formulation.   15. A method according to claim 14, wherein the zeolite is a hydrophilic zeolite. From gas or liquids supply stream comprising water to remove the water, the molecular sieve formulation produced by the method according to have been or claim 14 or 15 according to any of claims 1 to 13 use. Use of a molecular sieve formulation as claimed in any of claims 1 to 13 or produced by the method of claim 14 or 15 for drying cracked gas. Use of a molecular sieve formulation as claimed in any of claims 1 to 13 or produced by the method of claim 14 or 15 for drying cracked natural gas.

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